Interior lighting system of a motor vehicle and a method for controlling the same

ABSTRACT

The invention relates to an interior lighting system for a motor vehicle which comprises a lighting device for lighting a motor vehicle interior and a control unit for regulating the brightness and/or the colour of the light emitted from the lighting device, and to a method for controlling the interior lighting system. The colour of the light emitted from the lighting device ( 12 ) can be automatically adjusted in accordance with at least one operating parameter and/or at least one parameter associated with the environment of the motor vehicle. Preferred parameters of this type are a deviation of an actual temperature from a predetermined desired temperature of the motor vehicle interior and/or the driving speed of a vehicle.

[0001] The present invention relates to an interior-lighting system of a motor vehicle and a method for its control, having the features of the generic part of independent claims 1 and 12.

[0002] At present, a typical interior lighting of a motor vehicle includes a lighting device disposed in the vehicle ceiling in the front area of the passenger compartment, emitting an essentially white light. Sometimes, additional light sources are assigned to this lighting device, for instance at the level of a rear seat bench or in the trunk. The interior lighting provides better orientation for persons getting in or out of the car as well as during loading and unloading of the vehicle. It is usually activated by the opening of a vehicle door, or by a central locking system of the vehicle with the aid of a control unit. The interior lighting comes on in response to a vehicle door being opened. After the door is closed, the interior lighting is turned off, directly or by a time delay, this sometimes being coupled to the starting of the engine.

[0003] After such a lighting device has been turned off, only an instrument light remains active whose brightness and—as known from EP 562 332 A1—whose color can be manually adjusted. The instrument light and possibly additional lighting devices for operating controls such as the door handle and cigarette lighter are not used to illuminate the interior and are expediently coupled to an activation of a vehicle's exterior lights.

[0004] The current interior-lighting systems for motor vehicles have the disadvantage that they are only activated in connection with the opening of a vehicle door and are turned off by the closing of the door, or by a brief delay, so that the interior remains dark during the predominant part of the actual vehicle operation. If an occupant wants to search for something or read a map in a dark vehicle environment, the interior lighting must be turned on manually, resulting in an attention loss for the traffic situation. Also, the stay in a dark environment is often perceived as unpleasant, and it promotes tiring of the driver as well.

[0005] From the Japanese-laid-open document 05 270 314, an interior lighting for busses is known where a color of the light emitted by the lighting can be changed as a function of an outside temperature. At high outside temperatures, a light perceived as cool is provided and a light perceived as warm when the outside temperature is low. The disadvantage of this design is that an outside temperature bears no relationship to an inside temperature of a subjective temperature perception of an occupant. Therefore, a lighting according to the cited document might even be perceived as distracting, in an extreme case.

[0006] The present invention is thus based on the object of proposing an interior lighting for motor vehicles and a method for is control by which it is ensured that a vehicle occupant is provided with optimum lighting at all times, and thus has a sense of well-being while inside the motor vehicle.

[0007] This object is achieved by an interior-lighting system having the features of claim 1 and a method for its control, having the features of claim 12.

[0008] The basic idea of the present invention is that at least one basic lighting of the interior is maintained while an occupant is present in the vehicle, by a light having a color that is perceived as pleasant. Therefore, the interior lighting system of a motor vehicle according to the present invention includes a lighting device, in which a color of a light emitted by the lighting device is automatically variable as a function of at least one operating parameter and/or at least one ambiency parameter of the motor vehicle.

[0009] According to an advantageous development of the present invention, the at least one ambiency parameter is the temperature prevailing outside the vehicle, measured by a temperature sensor.

[0010] In accordance with another advantageous development, at least one operating parameter of the motor vehicle controllable und/or controlled by a vehicle passenger, is detected and the color of the light emitted by the lighting device is automatically varied as a function of the at least one operating parameter.

[0011] The measures of the present invention ensure an illumination of the vehicle interior by a light that allows a passenger to easily see things in the interior and to read maps, for instance, at least for a brief time, without straining his eyesight. Naturally, the lighting device should be disposed in such a way, or its brightness be adjusted such that the driver does not encounter glare or that his perception is not impaired, and he is able to perceive the traffic conditions with sufficient contrast. By varying the color of the light emitted by the lighting device on the basis of at least one of the operating parameters controlled by the vehicle occupant, an atmosphere is created that is constantly adjusted to a subjective behavior and/or an occupant preference. This considerably contributes to the well-being of the vehicle's occupant and reduces stress, thereby actively increasing road safety.

[0012] It is preferably provided that the emitted color of the lighting device is variable as a function of a deviation of an instantaneous temperature from a setpoint temperature of the vehicle interior specified by a vehicle occupant. According to a preferred embodiment, the interior-lighting system includes for this purpose a sensor for detecting an operating state of an air-conditioner or a heating system, an output signal of the sensor being input by the control device. Alternatively, a temperature sensor for detecting a temperature of the interior may also be provided, the control unit comparing an output signal of the temperature sensor with a specified setpoint temperature. According to the present method, the light color of the second lighting device is varied as a function of the operating state of the air-conditioner or the heating system, or the deviation from the setpoint value. According to a preferred embodiment, a color perceived as cool is set if a cooling of the air-conditioner, a non-heating of the heating system or an exceeding of the setpoint temperature is detected. Conversely, a color perceived as warm is set when a heating of the air-conditioner or the heating system, or an undershooting of the setpoint temperature, is present. In this manner, deviations of the vehicle's inside temperature from a temperature individually preferred by the occupants may be compensated for, at least to some extent.

[0013] An advantageous embodiment of the interior-lighting system according to the present invention additionally provides that the color emitted by the lighting device be variable as a function of a speed of the motor vehicle specified by the car's driver. For this purpose, the interior-lighting system includes a sensor for detecting the vehicle speed, whose output signal is input by the control unit. This sensor may be an already present tacho sensor, for instance. It is preferably provided that a color be set that promotes concentration and/or is calming when a vehicle speed exceeds a specified threshold value. Green, for instance, is known as a color having such an effect. In contrast, blue light has proven to promote concentration at low speeds.

[0014] It is possible to optionally implement either the temperature-regulated or the speed-regulated color control of the lighting device, or a combination of both. In the latter case, it may be provided, for instance, that the light management be implemented in a temperature-dependent manner below a specified speed threshold, and, if this threshold is exceeded, the lighting is controlled to green light, based on speed.

[0015] According to a very advantageous embodiment, the lighting device includes at least two light sources, which may be controlled independently of one another, the at least two light sources emitting light of a different color. The color altogether emitted by the lighting device may be varied by increasing the brightness of a first light source and decreasing the brightness of a second light source. According to a special embodiment, a first light source of the lighting device emits white light, and the additional light source(s) emit(s) light of a different color. According to this embodiment, a white light of the lighting device is produced by increasing a brightness of the first light source and by decreasing the brightness of the at least one second light source, or by turning it off. An alternative embodiment of the interior-lighting system provides a white light of the lighting device to be producible by superimposing a plurality of light sources on the light. This may easily be realized by three light sources, which, for instance, emit light in the three basic colors red, yellow and blue which, when superposed, produce white light. By an appropriate mixing of these light sources, any desired other light color may be created.

[0016] In addition to the lighting device having variable light color, the interior lighting system may also include a standard lighting device, which essentially emits white light and whose brightness is controllable as a function of a vehicle door and/or a central locking system. If such a lighting system is provided, which supplies an interior lighting according to the related art by a bright white light when a passenger exits or enters, it is possible to omit the possibility of the first light producing white light according to present invention.

[0017] According to the present invention, the lighting device may encompass diffuse interior lighting, an indirect comfort light, a footwell light, a door-handle light, or a combination of these. In particular, the brightness of these components may also be controlled independently of one another.

[0018] According to a particularly preferred embodiment, the lighting device may be manually controlled by the vehicle occupants. In this context, it may be provided that the vehicle occupant is able to control the brightness or the color tone of the lighting device, or both, at any time.

[0019] According to a preferred embodiment, the interior-lighting system is turned on by the opening of a vehicle door, and is controlled to a bright and essentially white light. As already elucidated, this white interior lighting may be implemented either by an additional standard lighting device or the appropriately designed lighting device according to the present invention. It is also advantageously provided that the lighting device be controlled to a colored subdued light by closing the vehicle door, or by a specified delay, at the latest, however, by starting the engine. This should only occur when an occupant is inside the vehicle or until the vehicle is locked. Additionally, while the vehicle is operated the activation of the lighting device may also be made dependent on an exterior lighting of the vehicle being turned off. Given sufficient ambient light, an unnecessary turning on of the lighting device may be prevented in this manner.

[0020] Advantageous embodiments of the present invention are the subject matter of the dependent claims.

[0021] The present invention is explained below in more detail with the aid of exemplary embodiments and the corresponding drawings. The figures show:

[0022]FIG. 1 a schematic system of an interior lighting device according to an embodiment of the present invention; and

[0023]FIG. 2 a schematic system of an interior lighting device according to another embodiment of the present invention.

[0024] According to a first embodiment shown in FIG. 1, the interior-lighting system of a motor vehicle denoted as a whole by reference numeral 10, includes three light sources 14, 16, 18. The three light sources 14, 16, 18 each emit a light of a different color. According to the shown example, these are the basic colors red, yellow and blue. The brightness of the three light sources 14, 16, 18 may be controlled independently of one another by control device 20. A color of a light emitted altogether by lighting device 12 may be varied by decreasing or increasing the brightness of one or a plurality of light sources 14, 16, 18. A white light of lighting device 12 results from superimposing identical light intensities of the three light sources 14, 16, 18. The color of the light emitted by lighting device 12 is automatically varied as a function of at least one of the motor vehicle's operating parameters controlled by a vehicle occupant. For instance, the light color is varied as a function of a deviation between an instantaneous temperature and a setpoint temperature of the vehicle interior specified by a vehicle occupant. For this purpose, interior lighting system 10 includes a sensor 22, which detects an operating state of an air-conditioner and transmits an output signal to control unit 20. If sensor 22 detects a heating of the air-conditioner, control unit 20 controls lighting device 12 to a color perceived as warm, preferably a red tone, since a temperature of the vehicle interior apparently is below a setpoint temperature specified by a vehicle occupant. Conversely, a color perceived as cool, for instance blue, of lighting device 12 is set when sensor 22 detects a non-heating of the air-conditioner. In addition, the color of lighting device 12 may be controlled as a function of a vehicle speed. For this purpose, sensor 24, which may be a tacho sensor, for instance, transmits the instantaneous vehicle speed to control device 20 which—if a specified speed threshold has been exceeded—specifies a light color which promotes concentration and/or has a calming effect, preferably a green light. Of course, the light color of lighting device 12 may also be varied solely as a function of temperature or speed.

[0025] A further sensor 26 registers an opening or closing of the vehicle doors. In addition, it may also be coupled to a central locking system. As soon as sensor 26 detects an opening of a vehicle door or an unlocking of the vehicle locking system, control device 20 turns on lighting device 12 and controls it to a light and essentially white light, so that an orientation of an occupant during entering and exiting, or during a loading procedure, is facilitated. In response to the closing of the vehicle door, possibly by a brief delay or by starting the engine, the brightness of lighting system 12 is reduced and a color of the emitted light is regulated as a function of the signals of sensors 22, 24. In order to avoid an unnecessary operation of lighting device 12, it may additionally be made dependent on an outside brightness, which is most easily detected by a sensor 28, which determines whether an exterior lighting of the vehicle is turned on or off.

[0026] An alternative embodiment of an interior-lighting system is shown in FIG. 2. Elements that are identical to FIG. 1 are denoted by identical reference numerals. According to this embodiment, interior-lighting system 10, in addition to lighting device 12, includes a standard lighting device 30, which corresponds to an interior lighting according to the related art. Standard lighting device 30 emits an essentially white light and is preferably controlled as a function of the state of the vehicle doors or the vehicle locking system detected by sensor 26. While vehicle occupants enter, standard lighting device 30, preferably disposed on the vehicle rooflining, illuminates the interior. After the vehicle door has been closed or after the engine has been started, the brightness of standard lighting device 30 is abruptly or incrementally controlled downward, while the brightness of lighting device 12 is conversely increased. During vehicle operation, the color of the light emitted by lighting device 12 is controlled, in the manner already described, as a function of the air-conditioner (sensor 22) and/or the vehicle speed (sensor 24).

[0027] In the embodiment of the present invention shown in FIG. 2, lighting device 12 includes, for instance, an indirect comfort light, a footwell light and/or a door-handle light. On the other hand, according to the embodiment shown in FIG. 1, lighting device 12 should additionally include a diffuse interior lighting, which ensures the illumination required during entering and exiting as well as loading and unloading.

LIST OF REFERENCE NUMERALS

[0028]10 interior-lighting system

[0029]12 lighting device

[0030]14 light source

[0031]16 light source

[0032]18 light source

[0033]20 control device

[0034]22 sensor (air-conditioner/heating system)

[0035]24 sensor (vehicle speed)

[0036]26 sensor (vehicle door)

[0037]28 sensor (exterior lighting)

[0038]30 standard lighting device 

What is claimed is:
 1. Interior-lighting system of a motor vehicle, comprising a lighting device for illuminating a vehicle interior and a control unit for regulating a brightness and/or a color of an emitted light of the lighting device, wherein the color of the light emitted by the lighting device (12) is automatically variable as a function of at least one operating parameter and/or at least one ambiency parameter of the motor vehicle.
 2. The interior-lighting system as recited in claim 1, wherein the at least one ambiency parameter is the outside temperature measured by a temperature sensor.
 3. The interior-lighting system as recited in claim 1 or 2, wherein the at least one operating parameter is an operating parameter that is able to be controlled and/or is controlled by a vehicle occupant.
 4. The interior-lighting system as recited in one of the claims 1 through 3, wherein the color of the light emitted by the lighting device (12) is variable as a function of a deviation between an instantaneous temperature and a setpoint temperature of the vehicle interior specified by a vehicle occupant.
 5. The interior-lighting system as recited in claim 4, wherein the interior-lighting system (10) includes a sensor (22) for detecting an operating state of an air-conditioner or a heating system, and an output signal of the sensor (22) is input by the control device (20).
 6. The interior-lighting system as recited in claim 4, wherein the interior-lighting system (10) includes a temperature sensor (22) for detecting a temperature of the interior, and an output signal of the sensor (22) is input by the control device (20).
 7. The interior-lighting system as recited in one of the preceding claims, wherein the color of the light emitted by the lighting device (12) is variable as a function of a speed of the motor vehicle specified by a vehicle driver.
 8. The interior-lighting system as recited in claim 7, wherein the interior-lighting system (10) includes a sensor (24) for detecting the vehicle speed, whose output signal is input by the control unit (20).
 9. The interior-lighting system as recited in one of the preceding claims, wherein the lighting device (12) includes at least two light sources (14, 16, 18), which are able to be controlled independently of one another, the at least two light sources (14, 16, 18) emitting light of a different color.
 10. The interior-lighting system as recited in claim 9, wherein a first light source (14) of the lighting device (12) emits white light.
 11. The interior-lighting system as recited in claim 9, wherein a white light of the lighting device (12) is representable by superimposing the light of a plurality of light sources (14, 16, 18).
 12. The interior-lighting system as recited in one of the preceding claims, wherein the lighting device (12) includes an indirect comfort light, a footwell light, a door-handle light, or a diffuse interior lighting, or a combination of these.
 13. The interior-lighting system as recited in one of the preceding claims, wherein the lighting device (12) is controllable manually by the vehicle occupant.
 14. A method for controlling an interior-lighting system of a motor vehicle having a lighting device, a brightness and/or a color of an emitted light of the lighting device being able to be regulated, wherein at least one operating parameter and/or at least one ambiency parameter of the motor vehicle is detected and the color of the light emitted by the lighting device (12) is automatically varied as a function of the at least one operating parameter and/or at least one ambiency parameter.
 15. The method as recited in claim 14, wherein the outside temperature is detected as the at least one ambiency parameter and the color of the light emitted by the lighting device (12) is varied as a function of at least the detected outside temperature.
 16. The method as recited in claim 14 or 15, wherein the at least one operating parameter is an operating parameter which is able to be controlled and/or is controlled by a vehicle occupant.
 17. The method as recited in one of the claims 14 through 16, wherein the color of the light of the lighting device (12) is varied as a function of an operating state of an air-conditioner or a heating system or a deviation of an instantaneous temperature from a setpoint temperature of the interior.
 18. The method as recited in claim 17, wherein a color perceived as cold is set when a cooling of the air-conditioner, a non-heating of the heating system or an exceeding of the setpoint temperature is detected, and a color perceived as warm is set when a heating of the air-conditioner or the heating system or an undershooting of the setpoint temperature is detected.
 19. The method as recited in one of claims 14 through 18, wherein the color of the light of the lighting device (12) is varied as a function of a vehicle speed.
 20. The method as recited in claim 19, wherein a color promoting concentration and/or a calming color is set when a vehicle speed exceeds a specified threshold value.
 21. The method as recited in one of claims 14 through 19, wherein the lighting device (12) includes at least two light sources (14, 16, 18), the at least two light sources (14, 16, 18) emitting light of a different color, and a change in the color of the lighting device (12) is effected by increasing a brightness of a first light source (14) and by lowering the brightness of a second light source (16, 18).
 22. The method as recited in claim 21, wherein the first light source (14) emits white light and a white light of the lighting device (12) is produced by increasing a brightness of the first light source (14) and by decreasing the brightness of the at least one second light source (16, 18).
 23. The method as recited in claim 21, wherein a white light of the lighting device (12) is represented by superimposing the light of a plurality of light sources (14, 16, 18).
 24. The method as recited in one of claims 14 through 23, wherein the interior-lighting system (10) is turned on by the opening of a vehicle door, and is regulated to an essentially white, bright light.
 25. The method as recited in claim 24, wherein the lighting device (12) is regulated to a colored, subdued light when an occupant is present in the vehicle, by the closing of the vehicle door, or by a specified delay, at the latest, however, by starting the engine.
 26. The method as recited in one of claims 14 through 25, wherein the lighting device (12) is only activated during the vehicle operation when an exterior lighting of the vehicle is turned on. 